A fic about sniper fishing near a lake and stumbles upon tentaspy. First encounter went with sniper accidentally falling through a cave and tentaspy attacking him. He does not kill sniper however and returns him safely back to the lake. Second encounter is when tentaspy got injured and sniper offered him a bucket of fish. Third encounter, sniper went spelunking and got lost in the cave, and spy offered help... oh yeah, there's also hot springs and backstory of spy suffering from the experiments
Apologies, for the lack of spoiler warnings...sorry about that :(